Throttle Control for Engine Cranking Emission Reduction
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Solution Overview
Problem
Internal combustion engines emit excessive emissions during cold starts due to the catalytic converter not reaching operating temperature, leading to increased air and fuel intake, which results in higher emissions before the engine reaches optimal operating conditions.
Innovation Solution
A system that includes an engine cranking module and a throttle control module, which determines when the engine is cranking and adjusts the throttle to a fully closed position to limit volumetric efficiency by reducing air intake, thereby decreasing fuel injection and emissions, especially during cold starts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the throttle is fully open during engine cranking to ensure sufficient air intake for combustion, then the engine can start reliably, but excessive air intake causes increased fuel injection and higher emissions before the catalytic converter reaches operating temperature
Solution Approach 1:
The throttle position is dynamically adjusted based on engine operating conditions. During cranking, the throttle is controlled to a specific position (not fully open) to limit volumetric efficiency and reduce air intake. Once the engine reaches a predetermined speed threshold indicating successful startup, the throttle transitions to a fully open position for optimal performance. This dynamic adjustment resolves the contradiction by adapting throttle position to different operational phases.
Solution Approach 2:
The system changes the throttle opening parameter based on engine speed conditions. During cranking mode, the throttle opening is limited to a predetermined position that restricts air flow. After the engine accelerates past a threshold speed, the throttle parameter changes to full opening. This parameter change strategy allows the system to optimize for emissions reduction during startup while maintaining performance during operation.
2Object-generated harmful factors
If the throttle is limited during engine cranking to reduce air intake and emissions, then emissions decrease, but insufficient air intake may prevent reliable engine combustion and startup
Solution Approach 1:
The throttle control system dynamically adjusts opening based on real-time engine speed feedback. During the cranking phase, the throttle maintains a limited position to reduce emissions. Once the engine speed exceeds a predetermined threshold, indicating successful combustion establishment, the throttle dynamically opens to full position. This dynamic behavior ensures emissions reduction during startup while guaranteeing sufficient air intake for reliable combustion after startup.
Solution Approach 2:
The system performs preliminary throttle limitation during the cranking phase before the engine is fully operational. This preliminary action reduces emissions during the harmful cold start period. The predetermined speed threshold acts as a trigger that, when reached, automatically ends the preliminary limitation phase and transitions to normal operation, ensuring combustion reliability is established before full air intake resumes.
Data Source
AI summary
A system according to the principles of the present disclosure includes an engine cranking module and a throttle control module. The engine cranking module determines whether an engine is cranking based on at least one of an input received from an ignition system and engine speed, and generates a signal indicating whether the engine is cranking. The throttle control module selectively adjusts a throttle of the engine to a fully closed position when the signal indicates that the engine is cranking.